Approximate Optimal Disturbance Rejection For Nonlinear And Time-delay Systems With Disturbances

Strictly speaking, almost all practical control systems are often affected by external disturbances in nature, except for stochastic disturbances, there are external deterministic disturbances including step disturbance, slope disturbance, impulse disturbance, sinusoidal and periodical disturbance, and exosystem and so on, which widely exist in practical processes. So rejection or optimal damping of deterministic disturbances is widely applied to many application areas, such as aerospace, industry, mechanical engineering and ocean engineering. For example, one application area of interest is the active control for offshore structures, where the main disturbances affecting offshore structure performance are mainly from the wind or ocean wave forces. Where dynamic characteristic of inerratic ocean wave is known. Another application area is on systems affected by persistent disturbances is the flight attribute control through wind shear stresses, where the disturbance forces arise from a model for wind shear stresses based on harmonic oscillations. Optical and magnetic disk drives, and active noise control, etc. If we design the systems with external disturbances by using primary method without disturbance initial value, the control law obtained is not optimal, and has poor robustness about the external disturbances. Therefore, the analysis of the optimal control for nonlinear systems with external disturbances is appropriate for actual systems, and is one of the important control problems both in theory and in practice.Based on the present situation on the optimal control problem of...